Datasheet

TPS78915, TPS78918, TPS78925, TPS78928, TPS78930
ULTRALOW-POWER LOW-NOISE 100-mA
LOW-DROPOUT LINEAR REGULATORS
SLVS300A – SEPTEMBER 2000 – REVISED MAY 2001
8
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
TYPICAL CHARACTERISTICS
Figure 9
f – Frequency – Hz
1k 10k 100k
I
O
= 1 mA
V
I
= 4.3 V
0
800
500
100
700
200
300
600
400
100
I
O
= 100 mA
nV/ HzOutput Spectral Noise Density –
TPS78930
OUTPUT SPECTRAL NOISE DENSITY
vs
FREQUENCY
V
I
= 4 V
C
o
= 10 µF
C
(byp)
= 0.1 µF
Figure 10
f – Frequency – Hz
1k 10k 100k
0
1.6
1
2
0.2
1.4
0.4
1.8
0.6
1.2
0.8
100
C
(byp)
= 0.01 µF
V/ HzOutput Spectral Noise Density –
TPS78930
OUTPUT SPECTRAL NOISE DENSITY
vs
FREQUENCY
V
I
= 4 V
I
O
= 100 mA
C
o
= 10 µF
C
(byp)
= 0.1 µF
C
(byp)
= 0.001 µF
µ
Figure 11
150
100
50
0
0.00001 0.0001 0.001 0.01
RMS – Root Mean Squared Output Noise –
200
250
ROOT MEAN SQUARED OUTPUT NOISE
vs
BYPASS CAPACITANCE
300
0.1 1
(RMS)
Vµ
C
(bypass)
– Bypass Capacitance – µF
V
O
= 3 V
V
O
= 1.5 V
V
I
= 4 V
C
o
= 4.7 µF
Figure 12
100 1 M10 1 k
f – Frequency – Hz
10 k
– Output Impedance –Z
o
Ω
OUTPUT IMPEDANCE
vs
FREQUENCY
0
1.6
1
2
0.2
1.4
0.4
1.8
0.6
1.2
0.8
100 k
I
O
= 100 mA
I
O
= 1 mA